There are several types of port available to connect a Cisco router. We can group these types of a port in the following categories:

In-band interfaces and ports – In-band router interfaces are the LAN (i.e. Gigabit Ethernet, Fast Ethernet, and Ethernet ) and WAN (i.e., eHWICs) interfaces configured with IP addressing to carry user traffic. Ethernet is the most common LAN connections. DSL and serial ports are the common WAN connections.

Out-of-Band Interfaces and Ports All Management ports including console and AUX ports are the types of out-of-band access interfaces. Out-of-band access refers to access using a dedicated management channel that is used for configuration and management. The Console and AUX ports to configure, manage and troubleshoot the router. These ports are not used for user traffic.

Establishing a connection to Cisco router

There are several ways to access a user EXEC mode in the CLI environment on the Cisco routers.

Console

Consol port provides Out-of-band access to Cisco router. This is a physical management access port to a Cisco device. This port is the most important port in Cisco devices, therefore; each Cisco router and switch must have a console port. The console port connects a computer directly to a router or switch. The console cable is necessary for initial configuration of a Cisco device. Because there is no more SSH, HTTP, HTTPS and telnet configured initially to connect the router.

The console cable connects a computer to the router via the console port. Figure 1 show the console port and Figure 2 show the console cable. A console cable is a special cable. One end of the cable is the RJ49 type and a DB9 to the RJ45 converter molded on the other end.

Secure Socket Shell (SSH)

SSH is a network protocol that provides remotely establishing a secure CLI connection through a virtual interface, over a network.SSH provides strong authentication and secures encrypted communication. Many network administrator uses SSH for managing systems remotely. SSH connections must active networking services on the device including an active interface configured with an IP address so SSH required in-band connection method

Telnet

A Telnet is another remote access method just like SSH but it is an insecure method. telnet establishing a CLI session through a virtual interface, over a network. Telnet does not give a securely encrypted connection. User authentication, passwords, and commands are sending over the network in plaintext. Telnet is also the in-band connection method.

Aux port

Some routers may also support a legacy auxiliary port to set up a CLI session remotely using a modem. Similar to a console connection, the AUX port is out-of-band and does not need networking services to be configured or available.

Generally, the putty software provides remote connectivity over different protocol and different way. A putty is a third-party software which is download here